Sink stopper



FIG. 1 is a top plan view of a sink stopper showing our new design;

FIG. 2 is a cross sectional view taken on line 2--2 of FIG. 1; and

FIG. 3 is a cross sectional view taken on line 3--3 of FIG. 1. 

The ornamental design for a sink stopper, as shown. 